The present invention is related to voltage regulators. More particularly, the present invention is related to circuits, systems and methods for maintaining voltage regulators at a desired loading condition.
A prior art regulated system 100 is depicted in FIG. 1. Regulated system 100 includes a voltage regulator 110 that regulates an input voltage 102, and outputs a regulated voltage 120 to an overall load 140. Voltage regulator 110 includes an operational amplifier 112 receiving input voltage 102 and driving a FET 114. The drain of FET 114 is tied to a voltage source 122, and the source of FET 114 drives regulated voltage 120. A feedback loop of operational amplifier 112 is driven by the regulated voltage signal as divided by resistors 116, 118.
Overall load 140 includes a drive load 132 and a dummy load 136. Dummy load 136 is a resistive load, and is included to assure that voltage regulator 110 is always supplying at least some load. By maintaining at least some loading on voltage regulator 110, operational amplifier 112 is maintained in a desired range of operation and regulated voltage 120 is maintained relatively constant. However, maintaining minimum loading through use of dummy load 136 is wasteful. In particular, dummy load 136 is always drawing current from voltage regulator 110 which is dissipated as heat. Both the heat and the wasted current are undesirable.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced circuits, systems and methods for regulating voltages.